Which type of rock is formed by the crystallization of magma?

The correct answer is igneous rock, which is formed through the crystallization of magma. When magma cools and solidifies, the minerals within it crystallize and form a rock. This process can occur either beneath the Earth's surface, resulting in intrusive igneous rocks, or on the surface through volcanic activity, leading to extrusive igneous rocks. The composition of the magma, the rate at which it cools, and other geological factors influence the characteristics of the resulting igneous rock, such as its texture and mineral content. Understanding the formation of igneous rocks is fundamental in geology, as they are one of the three primary rock types, alongside metamorphic and sedimentary rocks.